Condition-monitoring electrical switch

ABSTRACT

An electrical switch adapted to monitor relative axial movement between the first member and a second member, the switch including an electrically nonconductive housing supporting a plurality of electrical conductors, a first sliding block having a ramp surface thereon mounted on one of the first and second members, a bus bar mounted on the first sliding block and having piercing elements thereon, and a second sliding block having a ramp surface thereon in sliding engagement with the ramp surface on the first sliding block, the second block being rigidly connected to the other of the first and second members. In response to relative axial movement between the members, the second sliding block wedgingly moves the first sliding block to a position wherein the piercing elements breach the housing and simultaneously contact each conductor so that an electrical potential on any one conductor is applied to all of the conductors.

States Patent Farrell et al.

[54] CONDITION-MONITORING ELECTRICAL SWITCH [72] Inventors: Robert C. Farrell, Saginaw; Thomas J.

Milton, Bay City, both of Mich.

[73] Assignee: General Motors Corporation, Detroit,

Mich.

[22] Filed: Feb. 25, 1971 [21] Appl.No.: 118,906

[52] [1.8. CI JOB/61.08, 200/153 LA, 339/98 [51] Int. Cl. ..H01h 3/16 [58] FieldofSearch ..200/168 E, 166CT,61.08, 153 LA;

3,489,981 l/1970 Corletal. ..339/99R Feb. 29, 1972 Primary ExaminerRobert K. Schaefer Assistant ExaminerM. Ginsburg Att0rneyW. E. Finken and D. L. Ellis [5 7] ABSTRACT An electrical switch adapted to monitor relative axial movement between the first member and a second member, the switch including an electrically nonconductive housing supporting a plurality of electrical conductors, a first sliding block having a ramp surface thereon mounted on one of the first and second members, a bus bar mounted on the first sliding block and having piercing elements thereon, and a second sliding block having a ramp surface thereon in sliding engagement with the ramp surface on the first sliding block, the second block being rigidly connected to the other of the first and second members. In response to relative axial movement between the members, the second sliding block wedgingly moves the first sliding block to a position wherein the piercing elements breach the housing and simultaneously contact each conductor so that an electrical potential on any one conductor is applied to all of the conductors.

3 Claims, 5 Drawing Figures Patented Feb. 29, 1972 Z I w w, \w a -w w m a an M M (w fl w a w a, i. 5 w

ATTORNEY CONDITION-MONITORIN G ELECTRICAL SWITCH This invention relates generally to electrical switches and more particularly to a switch operative to monitor the condition of a pair of normally relatively stationary members and automatically activate warning devices in the event relative movement occurs between the members.

Many examples can be cited of mechanical apparatus wherein a pair of members normally function as a single, rigid unit with relative movement therebetween occurring only in unusual circumstances and representing a malfunction of the apparatus. One such example is the energy-absorbingsteering column of a modern automobile wherein a lower mast jacket is rigidly supported on the vehicle body and has an upper mast jacket projecting from the outer end thereof and maintained in normally stationary relation thereto by an energy-absorbing means. Collapse of the steering column is characterized by telescoping movement of the upper mast jacket over the lower mast jacket, the relative movement obviously indicating a malfunction of the vehicle.

In the example cited, it may be desirable to alert other motorists to the malfunction a sufficient distance away for them to take proper action. On modern automobiles the means for providing such warning already exists in the form of flashing lamp units, energization of which other motorists have come to associate with vehicle malfunctions. Conventionally, these flashing lamp units are manually actuable at the discretion of the vehicle operator. In cases of severe malfunction, such as collapse of the steering column, it may be desirable to circumvent the manual switch in the flashing lamp circuit so as to relieve the operator of the burden of activating the warning lamps. An electrical switch according to this invention provides improved means for actuating the warning lamps in response to severe malfunctions while permitting ordinary manual operation of the lamps during normal operation of the vehicle.

Accordingly, the primary feature of this invention is that it provides a new and improved electrical switch which continuously monitors the condition of a pair of normally relatively stationary members and which automatically energizes one or more warning devices when a malfunction occurs which initiates relative movement between the members. Another feature of this invention is that it provides a switch of the described character including a housing adapted to insulatingly support a plurality of conductors and a bus bar adapted to pierce the insulation of the housing and electrically connect the conductors in response to relative movement between the members being monitored. Still another feature of this invention resides in the means provided to initiate piercing movement of the bus bar, such means including a pair of sliding blocks having complementary ramp surfaces thereon, a first of the blocks being rigidly coupled to one of "the members being monitored and the second block being movable with the other of the members being monitored so that movement of the one member relative to the other causes relative sliding movement between the ramp surfaces and wedging of the second sliding block to a position forcing the bus bar to pierce the insulation of the housing.

These and other features of this invention will be readily apparent from the following specification and from the drawings wherein:

FIG. 1 is a perspective view of an electrical switch according to this invention associated with a pair of telescopically r elated tubular members;

FIG. 2 is an enlarged sectional view taken generally along the plane indicated by lines 2-2 in FIG. 1 and showing the switch in normal inactive condition;

FIG. 3 is similar to FIG. 2 but showing the switch in active condition;

FIG. 4 is an exploded perspective view of an electrical switch'according to this invention; and

FIG. 5 is a-schematic diagram of a typical electrical circuit incorporating a switch according to this invention.

Referring now to FIGS. 1 and 5, an electrical switch according to this invention designated generally 10 is shown monitoring a pair of telescopically related tubular members 12 and 14 which represent, respectively, the upper and lower mast jackets of a typical energy absorbing vehicle steering column. The member 14 is maintained in generally rigid relation to the vehicle body while the member 12 is maintained stationary relative to the member 14 by energy-absorbing means, not shown. When an impact is experienced by the member 12, the energy-absorbing means distort and the member 12 moves telescopically downward over member 14. Associated with the switch 10 are a plurality of warning lamps 16 adapted to flash on and off when energized and a manually operable switch 18. The switch 18 is electrically connected by a conductor 20 to an energy source such as a conventional battery 22. The switch 18 is also electrically connected to each of the warning lamps 16 by a main conductor 24 and a plurality of a branch conductors 26, 28, 30 and 32; As best seen in FIG. 5, when the switch 18 is closed, as might occur when a vehicle operator desires to stop his vehicle at the side of the roadway, the warning lamps are energized. As described hereinafter, the switch 10 functions to electrically connect each of the warning lamps 16 to the battery 22 independently of the switch 18 in the event that relative telescoping movement occurs between the tubular members 12 and 14.

As seen best in FIGS. 1 through 4, the switch 10 includes a support base 34 having a pair of mounting lugs 36 interconnected by a channel portion 38 having therein at one end a slot 40. A U-shaped cap 42 including a pair of lugs 44, a pair of oppositely disposed inwardly projecting tabs 46 and a threaded aperture 48 is adapted to fit over the base with lugs 44 on the cap in register with the lugs 36 on the base, the cap and base being rigidly fastened together by a pair of capscrews 50 and 52. Capscrew 52 is somewhat longer than capscrew 50 so as to engage a threaded aperture 54 in the tubular member 12 and thereby attach the stitch 10 to the tubular member 12 for axial movement as a unit therewith.

As seen best in FIGS. 2, 3 and 4, the switch 10 further includes a generally rectangular housing 56 having a plurality of passages 58 extending therethrough. The housing 56 is fabricated from an electrically nonconductive material such as plastic or hard rubber and is performed such that each passage 58 includes a thin wall section as at 60. The housing 56 further includes a pair of downwardly opening receiving slots 62 disposed at opposite ends thereof, the slots 62 being adapted to receive tabs 46 on the support cap 42 such that downward movement, FIGS. 2 and 3, of the housing relative to the cap is restricted. A capscrew 64 threadedly received in aperture 48 in the cap is brought into engagement with the upper surface of the housing to restrict upward movement of the latter, the housing thus being rigidly supported on the cap.

As seen best in FIGS. 1, 2 and 3, each of the conductors 20, 26, 28, 30 and 32 passes through and is closely received in a respectiveone of the passages 58 in the housing. It will, of course, be apparent that the housing 56 might be adapted to serve as a conveniently located junction block. Such a modification would merely entail severance of each conductor at the housing and the placement on opposite severed ends of detachable pin and socket-type contacts, the contacts being insulatingly supported in a conventional manner in the passages in the housing.

Referring now to FIGS. 2, 3 and 4; a first sliding block 66, fabricated from electrically nonconductive material such as hard rubber, having a flat surface 68 and an inclined ramp surface 70 is supported in the channel portion 38 of the support base 34 for unitary movement therewith and for generally vertical movement relative thereto. An electrically conductive bus bar 72 is rigidly secured to the first sliding block 66 on the flat surface 68 of the latter, the bus bar including a plurality of integral generally vertically extending piercing elements 74. The piercing elements are separated by distances corresponding to the intervals between respective ones-of the conductors passing through the housing 56.

The ramp surface 70 on the first sliding block 66 slidably engages a complementary ramp surface 76 on a second sliding block 78, the latter being slidably received in channel portion 38 of the support base 34. As seen best in FIGS. 2, 3 and 4, an integral leg 80 projects downwardly from the second sliding block through slot 40 in the support base 34 and is tightly received in an aperture 82 in the tubular member 14. The second sliding block is thus supported on the tubular member 12 for movement relative thereto as a unit with the tubular member 14 between a first position, FIG. 2, and a second position, FIG. 3. 1

During normal operation of the vehicle, the elements of the switch are situated as shown in FIG. 2, the first sliding block being in a retracted position corresponding to a position of the bus bar 72 wherein the piercing elements 74 thereon shown as partially piercing the housing 56, however, they can be remote from the housing 56. Accordingly, the conductor and the branch conductors are unaffected by the switch 10 and the switch 18 remains operative to energize the lamps 16 at the discretion of the vehicle operator. In an unusual situation, as when forces on the steering column initiate energy-absorbing collapse thereof with tubular member I2 telescoping over tubular member 14, the second sliding block 78 is caused to move rightwardly relative to the support base 34 from a first position shown in FIG. 2 to a second position shown in FIG. 3. As the second sliding block moves rightwardly relative to the support base, inclined ramp surface 76 thereon wedges under inclined ramp surface 70 on the firstsliding block 66 initiating vertical movement of the latter relative to the support base from the retracted position to an extended position, FIG. 3. As the first sliding block 66 moves vertically, the piercing elements 74 on the bus bar first contact the thin-wall section 60 of the housing and then are forced through the thin-wall section and the insulating portion of the conductors to engage the electrically conductive portions of the corresponding conductors. As. seen best in FIG. 5, when contact is so made, the switch 18 is effectively short circuited and the electrical potential at conductor 20 is applied to each of the branch conductors 26, 28, 30 and 32 to automatically energize each of the flashing lamps 16. With the flashing lamps so energized, oncoming motorists are apprised of the vehicle malfunction in time to take precautionary measures.

Having thus described the invention, what is claimed is:

I. An electrical switch adapted to monitor the condition of a pair of members normally stationary with respect to each other and to automatically complete an external electrical circuit in response to relative movement between said members, said electrical switch comprising, a housing fabricated of electrically nonconductive material and receiving therein a plurality of electrical conductors at least one of which is constantly maintained at an electrical potential, means rigidly attaching said housing to one member of said pair of members, an electrically conductive bus bar, a plurality of electrically conductive piercing elements, means rigidly attaching each of said piercing elements to said bus bar at intervals corresponding to the spacing between said conductors in said housing, means supporting said bus bar on said one member for bodily movement relative thereto between a retracted position remote from said housing and an extended position wherein said piercing elements extend through said housing and engage respective ones of said conductors to thereby apply said potential to each of said conductors and during which movement said piercing elements forcibly breach portions of said housing adjacent respective ones of said conductors, and drive means responsive to relative movement between said members to forcibly move said bus bar from said retracted to said extended position thereof.

2. An electrical switch adapted to monitor the condition of a pair of members normally stationary with respect to each other and to automatically complete an external electrical circuit in response to relative movement between said members, said electrical switch comprising, a housing fabricated of electrically nonconductive material and receiving therein a plurality of electrical conductors at least one of which is constantly maintained at an electrical potential, means rigidl attaching said housing to one member of sard pair of mem ers,

an electrically conductive bus bar, a plurality of electrically conductive piercing elements, means rigidly attaching each of said piercing elements to said bus bar at intervals corresponding to the spacing between said conductors in said housing, a first sliding block having a ramp surface thereon, means rigidly attaching said bus bar to said first sliding block, means supporting said first sliding block on said one member for bodily movement relative thereto between a retracted position wherein said piercing elements on said bus bar are remote from said housing and an extended position wherein said piercing elements on said bus bar extend through said housing and engage respective ones of said conductors to thereby apply said electrical potential to each of said conductors and during which movement said piercing elements breach portions of said housing adjacent respective ones of said conductors, a second sliding block having a ramp surface thereon, means supporting said second sliding block on said one member for bodily movement relative thereto between first and second positions, said ramp surface on said first sliding block being engaged on said ramp surface on said second sliding block so that movement of the latter from said first to said second position wedgingly moves the former from said retracted to said extended position, and means rigidly connecting said second sliding block to the other member of said pair of members so that relative movement between said pair of members initiates movement of said second sliding block from said first to said second position thereof.

3. An electrical switch adapted to monitor relative axial movement between a first member and a second member and to automatically complete an external electrical circuit in response to such relative axial movement, said electrical switch comprising, a housing fabricated from electrically nonconductive material and having a plurality of passages extending therethrough, a plurality of said passages receiving therethrough respective ones of a plurality of electrical conductors at least one of which is maintained at an electrical potential, a support member, means rigidly mounting said housing on said support member, means rigidly attaching said support member to one of said first and said second members for axial movement as a unit therewith, an electrically conductive bus bar having a plurality of integral piercing elements spaced at intervals corresponding to the spacing between said conductors in said housing, a first sliding block having a fiat surface and an inclined ramp surface, means mounting said bus bar on said first sliding block on said flat surface thereof, means supporting said first sliding block on said support member for bodily movement relative thereto in a direction perpendicular to the direction of said axial movement between a retracted position wherein said piercing elements on said bus bar are remote from said housing and an extended position wherein respective ones of said piercing elements extend through said housing and engage corresponding ones of said conductors to thereby apply said potential to each of said conductors, a second sliding block having an inclined ramp surface thereon, means mounting said second sliding block on said support member for bodily movement relative thereto between a first position and a second position, said inclined ramp surface on said first sliding block being slidably engaged on said inclined surface of said second sliding block so that bodily movement of the latter from the first to the second position wedgingly moves the former from the retracted to the extended position thereof, and means rigidly connecting said second sliding block to the other of said first and said second members so that relative axial movement between said first and said second members initiates bodily movement of said second sliding block from the first to the second position thereof. 

1. An electrical switch adapted to monitor the condition of a pair of members normally stationary with respect to each other and to automatically complete an external electrical circuit in response to relative movement between said members, said electrical switch comprising, a housing fabricated of electrically nonconductive material and receiving therein a plurality of electrical conductors at least one of which is constantly maintained at an electrical potential, means rigidly attaching said housing to one member of said pair of members, an electrically conductive bus bar, a plurality of electrically conductive piercing elements, means rigidly attaching each of said piercing elements to said bus bar at intervals corresponding to the spacing between said conductors in said housing, means supporting said bus bar on said one member for bodily movement relative thereto between a retracted position remote from said housing and an extended position wherein said piercing elements extend through said housing and engage respective ones of said conductors to thereby apply said potential to each of said conductors and during which movement said piercing elements forcibly breach portions of said housing adjacent respective ones of said conductors, and drive means responsive to relative movement between said members to forcibly move said bus bar from said retracted to said extended position thereof.
 2. An electrical switch adapted to monitor the condition of a pair of members normally stationary with respect to each other and to automatically complete an external electrical circuit in response to relative movement between said members, said electrical switch comprising, a housing fabricated of electrically nonconductive material and receiving therein a plurality of electrical conductors at least one of which is constantly maintained at an electrical potential, means rigidly attaching said housing to one member of said pair of members, an electrically conductive bus bar, a plurality of electrically conductive piercing elements, means rigidly attaching each of said piercing elements to said bus bar at intervals corresponding to the spacing between said conductors in said housing, a first sliding block having a ramp surface thereon, means rigidly attaching said bus bar to said first sliding block, means supporting said first sliding block on said one member for bodily movement relative thereto between a retracted position wherein said piercing elements on said bus bar are remote from said housing and an extended position wherein said piercing elements on said bus bar extend through said housing and engage respective ones of said conductors to thereby apply said electrical potential to each of said conductors and during which movement said piercing elements breach portions of said housing adjacent respective ones of said conductors, a second sliding block having a ramp surface thereon, means supporting said second sliding block on said one member for bodily movement relative thereto between first and second positions, said ramp surface on said first sliding block being engaged on said ramp surface on said second sliding block so that movement of the latter from said first to said second position wedgingly moves the former from said retracted to said extended position, and means rigidly connecting said second sliding block to the other member of said pair of members so that relative movement between said pair of members initiates movement of said second sliding block from said first to said second position thereof.
 3. An electrical switch adapted to monitor relative axial movement between a first member and a second memBer and to automatically complete an external electrical circuit in response to such relative axial movement, said electrical switch comprising, a housing fabricated from electrically nonconductive material and having a plurality of passages extending therethrough, a plurality of said passages receiving therethrough respective ones of a plurality of electrical conductors at least one of which is maintained at an electrical potential, a support member, means rigidly mounting said housing on said support member, means rigidly attaching said support member to one of said first and said second members for axial movement as a unit therewith, an electrically conductive bus bar having a plurality of integral piercing elements spaced at intervals corresponding to the spacing between said conductors in said housing, a first sliding block having a flat surface and an inclined ramp surface, means mounting said bus bar on said first sliding block on said flat surface thereof, means supporting said first sliding block on said support member for bodily movement relative thereto in a direction perpendicular to the direction of said axial movement between a retracted position wherein said piercing elements on said bus bar are remote from said housing and an extended position wherein respective ones of said piercing elements extend through said housing and engage corresponding ones of said conductors to thereby apply said potential to each of said conductors, a second sliding block having an inclined ramp surface thereon, means mounting said second sliding block on said support member for bodily movement relative thereto between a first position and a second position, said inclined ramp surface on said first sliding block being slidably engaged on said inclined surface of said second sliding block so that bodily movement of the latter from the first to the second position wedgingly moves the former from the retracted to the extended position thereof, and means rigidly connecting said second sliding block to the other of said first and said second members so that relative axial movement between said first and said second members initiates bodily movement of said second sliding block from the first to the second position thereof. 